Heat exchanger for refrigerating systems



C. B. DEMANN HEAT EXCHANGE FOR REFRIGERATING SYSTEMS Filed July 17, 1955'INVENTOR/ 62:71am: 2., .DEMHIVN HIS ATTORNEYS.

Patented Oct. 6, 1936 UNITED STATES PATENT OFFICE HEAT EXCHANGER FORREFRIGERATING SYSTEMS Application July 1'1, 1935, Serial No. 31,876

/ 7 Claims.

This invention relates to heat exchangers and particularly to thebonding of a plurality of pipes or tubes to a header of such exchangers.

Heretofore, in the construction of water cooled condensers ofrefrigerating systems for example,

considerable difficulty has been experienced in securing the ends ofwater circulating pipes or tubes to a heavy metal header which serves asa closure for a container into which compressed refrigerant is depositedand adapted to be cooled and liquefied. This difficulty was occasionedby the fact that the thick metal header caused heat being appliedthereto at the ends of a tube adapted to be bonded to the header, to bedissipated or carried away from the points or surfaces to be bondedtogether more rapidly than would cause fluid-tight bonding of the tubeto the header. My invention is therefore directed to overcoming thedifficulty heretofore encountered in the bonding of ends of tubes orpipes to a metal header.

An object of my invention is to provide an improved low cost heatexchanger construction.

Another object of my invention is to provide an improved constructionofa header for, a heat exchanger to which header a plurality of fluidconveying pipes or tubes are secured.

A further object of my invention is to provide a header of a heatexchanger with thin walled tube-attaching portions remote from the thickmain body portion of the header so as to permit rapid and efiicientfluid-tight bonding of the ends of tubes to the header.

Further objects and advantages of the present invention will be apparentfrom the following de scription, reference being had to the accompanyingdrawing, wherein a preferred form of the present invention is clearlyshown.

In the drawing:

Fig. l is a sectional view taken on the line ll of Fig. 2 through a heatexchanger of a refrigerating system shown diagrammatically connectedwith the exchanger;

Fig. 2 is an end elevational view of the heat exchanger; 1

- Fig. 3 is an enlarged fragmentary sectional view showing a portion ofthe heat exchanger constructed in accordance with the present invention;and

Fig. 4 is a view similar to Fig. 3 showing a modified construction.

Referring to the drawing, for the purpose of i1- lustrating myinvention, I have shown diagrammatically in Fig. 1 thereof a closedrefrigerating system including a heat exchanger or condenser generallydesignated by the reference character In. The condenser or heatexchanger I0 comprises. an elongated cup-shaped metal member ll havingits open end closed by a relatively heavy or thick metal end plate orheader I2 which is welded thereto. A plurality of substantially U- 5shaped lengths of pipe or copper tubing l3 have their ends l4 secured toend plate or header l2 in a manner to be more fully describedhereinafter. An outer plate I6 is secured to header I 2 by bolts or anyother suitable securing means. 10 The outer plate I6 is provided with aplurality of hollowed-out portions l1 forming passages each of whichinterconnect one end of one of the U- shaped tubes I 3 with an end ofanother adjacent tube I3. The communication of passages I1 to- 15 getherwith the arrangement of tubes I 3 provide a series path of flow for afluid, such as water, to be circulated through the tubes l3 of condenserI0. The series path of flow through tubes I3 and passages ll includes aninlet connection l8 and an outlet connection l9 provided on the endplate IS. A plurality of fins 2| are secured to and extend transverselyto tubes l3 for increasing the heat transfer surface thereof. A heavyplate 22 located near the yoke portions of the U tubes I3 25 has anextending portion or device 23 which rests against the inner wall ofmember H to support the tubes and fins therein. The elongated metalcup-shaped member ll forms a tank around the tubes l3 and this tank isprovided with a fluid 30 inlet connection 25 and an outlet connection 26adapted to be connected with a refrigerating system. A bafiie 21 locatedbeneath the inlet connection 25 of the exchanger is provided with aplurality of small openings for distributing re- 35 frigerant circulatedto the exchanger I 0 along the length of the tubes l3.

The refrigerating system includes in addition to the condenser H) acompressor 28, operatively connected through suitable belt and pulley.con- 40 nections 29, to an electric motor 3|. The compressor 28 uponbeing operated by motor 31 withdraws gasified or evaporated refrigerant,through pipe 32, from an evaporator or cooling element 33. Theevaporated refrigerant is com.- 45 pressed and circulated underpressure, through pipe 34 and the inlet connection 25 on member ll, intothe tank or heat exchanger I ll. Any suitable cooling fluid such aswater is circulated from the inlet connection l8 through one of the 5passages I! in plate l6 (see Fig. 2) to one of the tubes I3. As beforestated the circulation of water through heat exchanger I0 is a seriespath of flow between the water inlet [8 and outlet l9 thereof. Thecirculation of water through the 55 exchanger therefore cools and causescondensation of the compressed refrigerant flowing through the openingsin baflie 21 and distributed' over the length of tubes l3. Refrigerantthus liquefied accumulates or collects in the bottom of tank In and isstored therein until admitted to evaporator 33 through the pipe orconduit 36 under control of a suitable expansion device or valve 31. Themotor 3| and consequently compressor 28 is intermittently operated byany suitable control switch 38 interposed in the electric power linesleading to motor 3|. Switch 38 is actuated by a bellows 39 connected, bya pipe 4|, to a thermostat bulb 42 located in thermal relation with theevaporator 33. It is to be understood that the bellows 39, pipe 4| andbulb 42 form a conventional and well-known thermostatic systemcontaining a volatile refrigerant for controlling operation of therefrigerant circulating means.

Since my invention relates to the heat exchanger or condenser Ill andparticularly to the construction of that portion of header l2 to whichthe tubes l3 are to be secured, I will now refer to Figs. 3 and 4 of thedrawing for describing my improvement. It will be noted that the headerl2 of condenser ||l (see Fig. 3) has tubular inserts 5|, preferably ofcopper material, brazed to the walls 53 of the tube receiving openingsprovided therein. The outer face of header I2 is counterbored as at 53adjacent the walls 52 of the opening and the ends 54 of inserts 5|,adapted to receive the ends M of the U-shaped tubes |3, extend beyondthe wall 52 into the space provided by the counterbore 53. The ends 54of inserts 5| have a tapered inner surface 55 providing-a space betweenthe outer wall of the tube 3 and the insert. The extension of the end 54of insert 5| into the space provided by the counterbore 53 thus locatesthe portions of tube l3 and insert 5| to be bonded together remote fromthe main thick body portion of header l2 and thereby permits heating andbonding of the portions to be secured together with solder withoutdanger of the heat being rapidly dissipated away from the points to bebonded by the body portion of header l2. Upon heating the end 54 ofinsert 5| and the end of the tube |3 solder will freely flow betweensame along the taper 55 and form a fluid-tight connection therebetween.The inserts 5| are brazed to header |2 prior to assembling the tubes |3thereto and it is obvious that the construction permits rapid heating ofthe ends 54 of inserts 5| and the ends of the tubes |3 located thereinto cause bonding together thereof at a point spaced from the main bodyportion of header I2.

"Tubes |3 may therefore be readily and quickly soldered to header l2 andthe header together with the tubes l3 securedthereto may then-beinserted in the elongated cup-shaped member through the open endthereof. The header I2 is then brazed or welded to the walls of memberII to form a closed tank. The end plate I6 is adapted to be bolted toheader l2 so that the grooves or passages provided therein aifordcommunication between certain ends of tubes l3 to form a series path offlow for the cooling fluid to' be circulated through the closed tankheat exchanger or condenser Hi.

In Fig. 4 of the drawing I have shown a-modifled form of constructionwhich permits the ends of the tubes l3 to be soldered or bonded directlyto the metal header I2. In this form of the invention a flange 56,formed on header l2 by cutting a groove 51 inwardly from the face of theheader, is tapered as at 58 for receiving solder to' be applied betweenthe outer wall of tube l3 and flange 58. The end of tube l3 and theflange 56 in this modified form of con- 'struction can be readilyheatedto a suflicient temperature to cause melting and flow of solderbetween the flange 55 and tube I3 for bonding the parts together sincethe points to be heated and bonded are remotely spaced from the mainthick body portion of header l2.

It will be seen from the foregoing that I have provided an improvedmethod or process of securing the ends of tubes or pipes to a heavymetal header. The improved construction insures that parts to be securedtogether can be heated to a soldering temperature without danger of heatbeing dissipated by the thick body portion of one of the metal partsfrom the points to be bonded together. My improvement greatlyfacilitates the manufacture and assembly of condensers or heatexchangers while at the same time reducing the cost of producing same.

While the form of embodiment of the invention as herein disclosedconstitutes a preferred form, it is to be understood that other formsmight be adopted, all coming within the scope of the claims whichfollow.

What is claimed is as follows:

1. A heat exchange structure comprising in combination, a plurality ofsubstantially parallel tubes, a header having a plurality of openingstherein for receiving the ends of said tubes, flange means extendingparallel with and laterally from the walls of said tube-receivingopenings and forming one wall of a hollowed-out portion provided in theface of said header adjacent said tube-receiving openings, and saidtubes extending parallel with said flange means and having their endsterminating adjacent the outer ends of the flange means and below theface of said header to thereby provide a joint located remote from themain body portion of said header adapted to be heated to cause bondingof the tubes to said header.

2. A heat' exchange structure comprising in combination, a plurality ofsubstantially parallel tubes, a header having a plurality of openingstherein for receiving the ends of said tubes, flange means extendingparallel with and laterally from the walls of said tube-receivingopenings and forming one wall of a hollowed-out portion provided in theface of said header adjacent said tube-receiving openings, and saidtubes extending parallel with said flange means and having their endsterminating adjacent the outer ends of the flange means and below theface of said header to thereby provide a joint located remote from themain body portion of said header adapted to be heated to cause bondingof the tubes to said header, said flangemeans having its surfaceadjacent the outer wall of a tube tapered to provide a space between thewall of the I tube and said flange for the reception of a bondingmaterial.

3. A heat exchange structure comprising in combination, a plurality ofsubstantially parallel tubes having a plurality of flns extendingtransversely thereto, a header having a plurality of openings therein,said headerhaving its face counterbored adjacent each of said openings,a tubular insert secured in each of said openings, said inserts adaptedto receivesaid tubes and having their ends extending from the walls ofsaid openings into the space provided by said counterbores to form awall of a groove surrounding the ends of said inserts, each of saidtubes having its end terminating adjacent the end of its cooperatinginsert, and the ends of said tubes and said inserts being disposed belowthe face of 'said header and providing surfaces remote from the mainbody portion of said header to be heated and bonded together.

4. A heat exchange structure comprising in combination, a plurality ofsubstantially parallel tubes having a plurality of fins extendingtransversely thereto, a header having a plurality of openings therein,said header havingits face counterbored adjacent each of said openings,a tubular insert secured in each of said openings, said inserts adaptedto receive said tubes and having their ends extending from the walls ofsaid openings into the space provided by said counterbores to form awall of a groove surrounding the ends of said inserts, each of saidtubes having its end terminating adjacent the end of its cooperatinginsert, the ends of said tubes and said inserts being disposed below thefaceof said header and providing surfaces remotefrom the main bodyportion of said header to be heated and bonded together, and saidinserts having their surface adjacent the outer wall of said tubestapered to provide a space between the wall of the tubes and saidinserts for the reception of a bonding material.

5. A heat exchange structure comprising in combination, a plurality oftubes, a header having a plurality of openings therein for receiving theends of said tubes, flange means extending parallel with and laterallyfrom the walls of said tube receiving openings and forming one wall of ahollowed-out portion provided in the face of said header adjacent saidtube receiving openings, at least a portion of said tubes extendingparallel with said flange means and having their ends terminatingadjacent the outer ends of the flange means and below the face of saidheader to thereby provide a joint located remote from the main bodyportion of said header adapted to be heated to cause bonding of thetubes to said header, and a closure member for said heat exchangestructure adapted to be clamped upon the face of said header, saidclosure member having passages formed therein providing comunicationbetween certain of said plurality of tubes.

6. A heat exchange structure comprising in combination, a plurality oftubes, a header having a plurality of openings therein for receiving theends of said tubes, flange means extending parallel with and laterallyfrom the walls of said tube receiving openings and forming one wall of ahollowed-out portion provided in the face of said header adjacent saidtube receiving openings, at least a portion of said tubes extendingparallel with said flange means and having their ends terminatingadjacent the outer ends of the flange means and below the face of saidheader to thereby provide a joint located remote from the main bodyportion of said header adapted to be heated to cause bonding of thetubes to said header, said flange means having its surface adjacent theouter wall of a tube tapered to provide a space'between the wall of thetube and said flange for the reception of a bonding material, and aclosure member for said heat exchange structure adapted to be clampedupon the face of said header, said closure member having passages formedtherein providing communication between certain of said plurality oftubes.

7. A heat exchange structure including a conduit and an end plate havingan opening in its main body portion receiving the conduit, flange meansextending from the wall of said conduitreceiving opening of said endplate and terminating inwardly of one face of said end' plate, saidflange means having its inner wall diverging laterally from the wall ofthe conduit-receiving opening in a direction toward said one face ofsaid end plate, said flange means forming a wall of a hollowed-outportion provided in said one face of said end plate adjacent saidconduit-receiving opening, and said conduit extending along said flangemeans and having its end terminating adjacent the outer end of theflange means and below said one face of said end plate to therebyprovide a joint located remote from the main body conduit-receivingportion of said end plate adapted to be heated to cause bonding of the

